Can I tether into my router

I’m not sure if this will help me but ya never know My question is;. Could I just plug my cell/USB into my router/modem? or even like my TV or the cable box and would that get me and my cell phone connected to WiFi ? Only have my old cellphone and it’s not letting me in to either Facebook nor play any of my games Basically nothing. Not even email, Google search or anything. Sincerely appreciate you, Malina. enter image description here